Fluorescent tube lighting fixture



Feb. 15, 1944. M. B. BECK FLUORESCENT TUBE LIGHTING FIXTURE Filed July12, 1940 2 Sheets-Sheet 1 INVENTOR, BY A Harris B. Beck.

WC ATTORNEYS Feb. 15, 1944. M. B. BECK FLUORESCENT TUBE LIGHTING FIXTUREFiled July 12, 1940 2 Sheets-Sheet 2 H mbw INVENTOR. Morris 3.5601. 9 i,6

ATTO EYS x QQ Patented 15, 1944 UNITED STATES PATENT OFFICE FLUORESCENTTUBE LIGHTING FIXTURE Morris B. Beck, Lawrence, N. Y.

Application July 12, 1940, Serial No. 345,022 3 Claims. (Cl. 240 -78)This invention relates generally to lighting fixtures, and moreparticularly it relates to lighting fixtures in which the illuminant isof the fluorescent tube type.

The general object of my invention is the provision in a lightingfixture of the character mentioned of a simple effective and inexpensiveconstruction.

A further object of my invention is the provision in a lighting fixtureof the fluorescent tube type of means for preventing the action of onetube on other tubes and thereby reducing their efllciency.

A further object of my invention is the provision in a lighting fixtureof the fluorescent tube type of a construction whereby a high degree ofcompactness without loss of efliciency may be attained.

Among the more particular objects of my invention is the provision in alighting fixture of the fluorescent tube type of a construction adaptedfor the attainment of efficient and uniform illumination and theelimination of glare.

Among the more particular objects of my invention is further theprovision in a lighting fixture of the fluorescent tube type of aconstruction for obtaining indirect as well as direct illumination.

These objects and such other objects as will hereinafter appear or bepointed out are attained in the illustrative embodiment of my inventionshown in the drawings, in which:

Figure 1 is a side elevational view of a fluorescent tube lightingfixture constituting one illustrative embodiment of my invention;

Figure 2 is an end elevational view thereof I Figure 3 is a bottom planview thereof with a portion broken away to expose the underlyingstructure;

Figure 4 is a fragmentary sectional view substantially on the line 44 ofFigure 1, looking in the direction of the arrows;

Figure 5 is a fragmentary side elevational view on an enlarged scale,portions being broken away to disclose the interior construction; and

Figure 6 is a transverse sectional view, substantially on the line 66 ofFigure 4, looking in the direction of the arrows, the upper portion ofthe fixture being omitted.

Fixtures using a plurality of fluorescent tubes as heretoforeconstructed have failed to attain the optimum because of the reductionin efficiency, due to the absorption by one tube of light from anothertube. Where it has been attempted to reduce this absorption by spacingthe tubes farther apart, the result has been an objectionable increasein the size of the fixture. This latter objection also exists where eachof the tubes is mounted in a casing or reflector open only at thebottom, because the reflector walls must be sufficiently spaced from thetube it encloses and have sufiicient surface area to preventoverheating.

I overcome these defects and attain the objects of my invention bymounting a plurality of fluorescent tubes side by side so that lighttherefrom may pass both upwards and downwards and so that air maycirculate around the tube and pass upward and downwards, whereby directas well as indirect illumination and adequate ventilation are provided.Between each pair of tubes I position a shield to prevent light from onetube reaching any other tube. By using such a shield a relatively closespacing of the tubes is possible without the objectionable absorption oflight from a given tube by adjacent tubes, hereinabove mentioned. Byusing shields that are in the form of peculiarly contoured reflectors Iobtain improved light distribution. To provide against glare I haveprovided a system of shields or louvers at the bottom of the fixture.

The construction hereinabove described generally and its function inefficiently providing pleasing illumination of high effectiveness willbe better understood during the course of the detailed description ofthe illustrative embodiment of my invention shown in the drawings, whichwill now follow.

At I0 I have shown a frame or casing comprising side walls II and endwalls l2 within which are supported in parallel relation a plurality offluorescent tubes I3 of conventional type. The tubes l3 have their endsmounted in sockets i l of conventional type, which sockets in turn aremounted on an inner wall l5 which is spaced from each end wall I2 so asto accommodate the electric Wiring IS.

The frame in is open at the top and open at the bottom. However in orderto avoid glare which may be objectionable where a person is situated insuch a portion of the room where the fixture is located that he is aptfrequently to look into the tubes carried by the fixture, I haveprovided a system of louvers II in the form of a network of plates thatcross each other, the longitudinally extending plates being shown at l8and the transversely extending plates at l9. Preferably the plates aremade thin so as not to obstruct light proceeding downward from the tubesor from the ceiling above th tubes and they are spaced sufficientlyclosely and are of such vertical extent as to perform their desiredshielding function.

I have found that if a plurality of luminous tubes are mounted inparallel relation that the light given off by the tube system is notequal in amount to the sum of the quantities of light given off by theindividual tubes. Thi is due to the absorption of light by any giventube. In order to prevent this absorption I have provided intermediateeach pair of tubes shielding means that will prevent the passage oflight from one tube into the other tube. Such shielding means I havefurther found may be advantageously combined with reflecting means, andstill further, where a casing such as the casing III is used, with meansfor rigidifying said casing. Such combined means is shown in the form oftubes I9a having four walls, and each tube 19a is positioned so that itssection is diagonally related to the adjacent fluorescent tubes I3 asshown in Figure 6 and also symmetrically relatively to the fluorescenttubes I3, that is to say th cross section of the tube will appearsubstantially as a diamond on a level with the fluorescent tube I3.

Consequently it will be observed that each fluorescent tube I3 throws aportion of its light up wardly and another portion of its lightdownwardly while rays proceeding laterally from the upper half of eachtube I3 strikes one of the faces of on of the tubes Iila on each side ofany given tube I3, and from these surfaces of the tube I9a it isreflected in an upward direction. Similarly light thrown off laterallyfrom the lower half of each tube I3 strikes another surface of a tube Ilid on each side thereof from which surface it is reflected downwardly.

It will be understood, of course, that the surfaces of the tubes Illaare of a character to perform effectively their reflecting function.They may also have their walls slightly concaved in transverse section,whereby parabolic reflection may be approximated.

The tubes are shown as having their ends secured to the inner walls I5.

Due to their being mounted in the walls IS the tubes also serve torigidify the casing an for this purpose their walls are madesufficiently heavy to perform this desired function.

The side walls II are shown provided with a.

plurality of openings 20 bounded by shielding Walls 2| and 22 the formerrunning along the upper edge of each opening 20 and the latter runningalong the lower edge and these wall are spaced from each other at theirinner sides so as to provide an opening 23 through which light from atube I3 can pass out laterally. The outer surfaces 24 and 25 f the walls2I and 22 respectively are made reflective and they are slightlyconcaved similarly to the walls of the tubes I So whereby they perform asimilar function.

It will be observed that the surfaces of the tubes I9a as shown inFigure 6 provide in effect parabolic reflection because of theirpeculiar contour and disposition and in the case of the tubes I3 thatare located nearest the walls II the refleeting surfaces 24 and 25 justdescribed cooperate with the reflecting surfaces of the tubes I9a toproduce the same effect.

It is to be understood that while the side openings 23 are of advantagefor particular purposes as tending to reduce objectionable contrastsbetween illuminated and unilluminated surfaces, that for other purposesit may be found preferable not to use them. It will further beunderstood that for particular purposes the sides I l of the casing maybe omitted entirely.

In order to prevent glare due to light proceeding laterally through theopenings 23 and 20 I may provide a translucent plate 26 closing eachopening 20. These plates may be of any suitable or preferred material. Ihave found the material known as Lumarith" particularly suitable for mypurposes. However it will be understood that for particular purposesother materials may be found more desirable.

The casing Ill may be further strengthened by straps 21 disposedtransversely thereto and having end portions 28 secured to one of thewalls II and vertically disposed portions 29 the latter serving to giverigidity in a vertical plane without obstructing substantially thepassage of light in a vertical direction. The straps 21 serve to affordanchorage for the tubes or pipes 30 by means of which the casing I0 ishung from the ceiling. In the drawings the pipes 30 are connected to acanopy 3I which is suitably secured to the ceiling C, as by means of thearrangement indicated at 32 by which the canopy is secured to a conduit33 projecting from or suitably secured to the ceiling. The canopy 3| ifdesired serve as a casing or compartment to enclose the auxiliaries 34which are required for the operation of the tubes I3. In order to add anornamental touch each pipe 30 may be enclosed by a tube 35 mounted overthe pipe in the customary conventional manner as by havin its endsseated in the seating ring 3 and any suitable or preferred forms offittin s 31. For certain purposes it may be found desirable to make thefittings 31 of jointed construction so that adjustment of the fixture isthereby made possible.

Each pipe 30 may pass through the horizontally disposed portion 38 ofone of the straps 31 and be anchored in a bushing 39 suitably sccured toone of the tubes I9a while the seating ring 36 will seat over the saidhorizontally disposed portion 38, whereby a secure and rigidconstruction is obtained.

It will now be understood that the fixture hereinabove described ishighly effective in securing efficient and uniform illumination and thatthe illumination is both direct and indirect and is free from anobjectionable glare.

While I have herein disclosed one illustrative embodiment of myinvention it will be understood that the same may be embodied in manyother forms as will be obvious to those skilled in the art. It willfurther be understood that the disclosure herein is by way ofillustration merely and is not to be interpreted in a limiting sense andthat I do not limit myself other than as called for by the prior art andthe scope of the claims.

Having thus described my invention and illustrated its use, what I claimand desire to secure by Letters Patent is:

1. A fluorescent tube lighting fixture consisting of a casing, means forsupporting said casing below a ceiling, said casing consisting of sidewalls and end walls but being open at the top and the bottom so as notto impede the passage of light and air in a vertical direction. aplurality of fluorescent luminous gaseous discharge tubes mounted insaid casing parallel to each other, shielding means between each pair ofadjacent tubes for preventing the passage of light from one tube intothe other, said shielding means being provided with reflecting surfacesso positioned as to reflect a portion of the light from each tube upwardand another portion downward, windows of translucent material in thosewalls of the casing that run parallel to the tubes, and a combinedshield and reflector respectively above said windows and below saidwindows for reflecting light from the adjacent tube respectivelyupwardly through the open top of the casing and downwardly through theopen bottom of the casing, said reflectors being positioned between thewindows of each side and the adjacent tube.

2. A fluorescent tube lighting fixture comprising a canopy adapted forattachment to a celling, auxiliaries for a fluorescent tube installationmoun said canopy, a casing provided with side walls and end walls, saidcasing being open at the top and at the bottom, sockets mounted on therespective end walls of said casing, each socket being adapted toreceive one end of a fluorescent tube thereinj reflecting surfacespositionedbneaeliside of the space adapted to receive a tub and saidsurfaces being adapted to reflect light from a tube in said space bothupwardly and downwardly, said reflecting surfaces between each pair oftubes being of such size and so positioned that light from one tube of apair is prevented from passing into the other tube of the pair, at leastone longitudinally extending opening in each side wall, said reflectingsurfaces between each outer tube and the adjacent side wall of thecasing being mounted in spaced relation, one to each side of saidopening, whereby light can pass between said reflecting surfaces andthrough the opening in said side wall.

3. A fluorescent tube lighting fixture comprising a canopy adapted forattachment to a ceiling, auxiliaries for a fluorescent tube installationmorihte'd'in said canopy, a casing provided with side walls and endwalls, said casing being open at the top and at the bottom, sockets 10mounted on the respective end walls of said casing, each socket beingadapted to receive one end of a fluorescent tube therein, reflectingsurfaces positioned on each side of the space adapted to receive a tubeand said surfaces being adapted to reflect light from a tube in saidspace both upwardly and downwardly, said reflecting surfaces betweeneach pair of tubes being of such size and so positioned that light fromone tube of a pair is prevented from pass- 20 ing into the other tube ofthe pair, at least one longitudinally extending opening in each sidewall, said reflecting surfaces between each outer tube and the adjacentside wall of the casing being mounted in spaced relation, one to each 25side of said opening, whereby light can pass between said reflectingsurfaces and through the opening in said side wall, transverse bracesconnected at their ends to the side walls of said casing and serving toreinforce said casing, said 30 braces offering little obstruction tolight in a vertical direction, and means for supporting the casing fromthe ceiling secured to said braces. MORRIS B. BECK.

